JPS6027539A - Polyester film having easy sliding property - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a slippery polyester film having a coating layer having a large number of microprojections on the film surface.

Prior Art Polyester films, especially biaxially oriented polyethylene terephthalate films, have excellent mechanical properties, heat resistance, and chemical resistance, so they are used in magnetic tapes, photographic films, packaging films, metallizing films for capacitors, and electrical insulation. The demand for it as a material for film, writing film, etc. has been growing particularly rapidly recently.

However, in order to smoothly produce polyester films and apply them to the above uses, it is necessary to improve the slipperiness of polyester films.

In other words, if the slipperiness of the film is insufficient in the case of a relatively thin polyester film, it will seriously hinder the operations such as winding, rewinding, coating, or slitting, and may cause wrinkles in the winding or dust adsorption due to generated static electricity. This results in undesirable phenomena such as

For example, when various molded products made by applying pressure molding or vacuum forming to unstretched or uniaxially stretched films of polyethylene terephthalate are stacked on top of each other, if the surface smoothness is insufficient, the molded products may be separated from each other. It can be pulled out smoothly, and therefore the assembly line work efficiency in the processing process is significantly reduced.

Conventionally, as a means to improve the aging properties of polyester films, films are formed using polyesters to which fine particles of various fillers such as silicon oxide, kaolin, talc, calcium carbonate, or alumina are added, followed by a biaxial stretching process. It has been put into practical use to take advantage of the phenomenon in which filler protrudes as minute protrusions on the film surface when the thickness of Finosim decreases. Similarly, as a technique for improving slipperiness using microprotrusions, a method is also known in which a catalyst used during polyester polymerization is converted into particles insoluble in the polymer.

Although these techniques have had some success in improving the slipperiness of films,
As a matter of course, the presence of the C microparticles leaves problems that need to be improved, such as lowering the transparency of the film or creating voids in the film composition. In particular, for polyester films used as raw materials for diazo films, metallizing films, photographic films, magnetic tape films, etc., the formation of oyohydride, which reduces the transparency of the film, is a serious problem. For example, magnetic film for video, for which demand has been increasing rapidly recently, is required to have particularly excellent electromagnetic properties to prevent undesirable phenomena such as dross (dropout) and color noise. . Therefore, the use of a polyester film as a raw material for such a video magnetic tape, in which filler-based microprotrusions occur almost equally on both sides of the film, is an important feature of the video magnetic tape. Although this improves the performance, it is undesirable because voids are generated and dropouts and color noise are less likely to occur.

In other words, in a magnetic tape made of a film that has minute protrusions equally on both surfaces, the magnetic paint layer is formed on the minute markings on the surface coated with magnetic paint, so the influence of these minute protrusions affects the magnetic paint layer. Although the magnetic coating layer rarely extends to the outer surface and forms a relatively flat magnetic coating layer surface, the microprotrusions are present on the other surface that does not have the magnetic coating layer. Therefore, in the wound magnetic tape, the minute protrusions on the other side are pressed against the relatively flat magnetic paint layer, so it is impossible to completely prevent these minute protrusions from being transferred to the magnetic paint layer. It becomes possible. In addition, the film obtained by the method of forming microprotrusions has the following properties:
They often have relatively coarse protrusions based on relatively coarse particles, and such coarse protrusions lead to the above-mentioned transfer.

Magnetic paint NK When a magnetic tape with unevenness comes into contact with a video hard head, space loss occurs, resulting in dropouts and color noise.

In order to improve these defects caused by microprotrusions, efforts have been made to further reduce the particle size of the microparticles, but in the end a compromise between transfer and slipperiness is required.

On the other hand, unlike the above method in which microparticles are added to polyester to form microprotrusions on the film surface, there is a method in which a specific coating liquid is applied to both sides of a film containing such microparticles and made from polyester. proposed a method of imparting slipperiness to the film by forming a worm-like film structure on both sides of the film.

Although this method uses a specific coating solution containing at least one of silicone or styrene-butadiene rubber and a water-soluble polymer compound, fine particles are added to the polyester in order to impart slipperiness to the film through post-treatment. [This is different from the method of imparting slipperiness to a film.

However, the problem with the above method is that sufficient slipperiness cannot be obtained unless a coating liquid is applied to both sides of the film to form a worm-like film structure on both sides of the film. If the worm-like film structure is formed on only one side of the film, the coefficient of friction between the surface with the worm-like film structure and the surface without it is still large, and sufficient slipperiness cannot be obtained.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a novel slippery polyester film having a coating layer of a specific composition having a large number of microprojections on either surface of the film. be.

Another object of the present invention is that the preferred slippery polyester film of the present invention has a coating layer having a large number of microprojections only on one side of the film, and has such a coating layer on the other side of the film. The object of the present invention is to provide a dual-structure, easy-slip polyester film in which the other surface is substantially flat.

Still another object of the present invention is to provide an easily slippery polyester film that does not cause or substantially does not cause transfer to a degree that is a nuisance for various uses, such as magnetic tape applications. It's about doing.

Another object of the present invention is to extrude molten polyester through a slit to form an unstretched thin film, and in a continuous process of sequentially biaxially stretching, while maintaining continuous production of the film.
The object of the present invention is to provide an industrially extremely advantageous method for producing a slippery polyester film by incorporating a procedure for forming a coating layer having a large number of microprojections on the surface of the film.

In addition, since the present invention uses a composition using water as a solvent, it has excellent advantages in terms of process, economy, and safety. On the other hand, in the prior art, the method of modifying the surface of a polyester film to make it slippery has been achieved in many cases by coating the surface layer of the film with a composition dissolved in an organic solvent. Ta. However, when such a method is applied during film formation, the use of organic solvents should be kept to a minimum as much as possible because the emitted organic solvents contaminate the surrounding environment and have undesirable adverse effects on safety and hygiene.

Structure of the Invention The above-mentioned object of the present invention is to apply a self-crosslinking polyurethane powder, silicone (13), and a roughening material (mainly containing 0) having an average particle size of 1 μm or less to the surface of a polyester film before the crystal orientation is completed. This is achieved by using an easily slippery polyester film that is coated with an aqueous solution, aqueous dispersion, or emulsion composition, and then solidified by crosslinking the coating film on the film surface to form a coating film with a large number of microprojections. Ru.

In the present invention, polyester is a linear saturated polyester synthesized from an aromatic dibasic acid or its ester-forming derivative and a diol or its ester-forming derivative.

Polyethylene terephthalate, polyethylene phthalate, polybutylene terephthalate, polyethylene-2
, 6-naphthalenecarboxylate, etc. Copolymers of these or blends of these with small proportions of other resins are also included. The polyester film of the present invention is obtained by melt-extruding the above linear saturated polyester resin, forming it into a film by a conventional method, and subjecting it to oriented crystallization and heat treatment crystallization. This polyester film was measured in a nitrogen stream (10
The value measured at a heating rate of ℃/min is usually 4 r
The crystals are oriented to such an extent that it exhibits llt/J/ or more.

In the present invention, a polyester film before complete crystal orientation refers to an unstretched film obtained by thermally melting a polymer and forming it into a film as it is; an unstretched film oriented in either the vertical direction or the horizontal direction. Ter-axially stretched film; furthermore, one that is stretched and oriented at a low magnification in two directions, the vertical direction and the horizontal direction (241+ stretched film before finally being re-stretched in the vertical or horizontal direction to complete oriented crystallization) ) etc.

The film of the present invention can be produced by applying a specific composition to an unstretched or at least uniaxially stretched film before crystal orientation is completed, and directly subjecting it to vertical stretching and/or horizontal stretching and heat setting. It is manufactured using a so-called in-line coating method.

It is difficult to obtain an effective surface condition even if the above-mentioned aqueous composition (liquid) is applied to an unstretched or at least uniaxially stretched film, left to stand for a period of time, and then biaxially stretched. However, it is an extremely important condition for achieving the present invention that the series of steps of coating, stretching, and heat setting are performed continuously.

The self-crosslinking polyurethane polymer that forms a coating film on the film surface of the present invention is a polyurethane polymer whose main polyurethane polymer contains reactive groups in its molecules, and is stabilized without causing any reaction in an aqueous liquid state. A crosslinked structure is generated by a reaction caused by heating or irradiation with energy rays.

The reactive groups contained in the self-crosslinking polyurethane polymer include an epoxy group, a blocked isocyanate group, a hydroxyl group, and a carboxyl group.

Carboxylic acid base, methyl group, alkoxyfurkyl group, ethyleneimide group, amine group.

Examples include acid anhydride groups and halogen groups. These reactive groups are present in appropriate combinations in the polyurethane polymer. As a combination of reactive groups, epoxy crystal/
Examples include carboxyl group, epoxy group/amino group, blocked in cyanate group/hydroxyl group, hydroxyl group/alkoxyalkyl group, epoxy group/acid anhydride group, etc.Also, like carboxylic acid group and methylol group, self-crosslinking is possible even when used alone. In some cases, it may have. These reactive groups or a combination of two or more reactive groups can be introduced into one type of polyurethane molecule or into two or more types of polyurethane molecules.

For example, ■ If polyurethane A contains epoxy groups and polyurethane B contains amine groups; ■ If polyurethane A contains epoxy groups and acid anhydride groups; ■ If polyurethane A contains epoxy groups and acid anhydride groups; ■ If polyurethane A contains epoxy groups and acid anhydride groups; When an epoxy group and a 7-mino group are included; ■When an epoxy group is included in polyurethane A and an acid anhydride group is included in polyurethane B;
■ When polyurethane A contains epoxy groups and carboxyl groups; ■ When polyurethane A contains blocked isocyanate groups and hydroxyl groups; ■ When polyurethane A contains blocked isocyanate and polyurethane B ■ When polyurethane contains a hydroxyl group; ■ When polyurethane contains a carboxylic acid zinc group; ■ When polyurethane contains a methylol group and a hydroxyl group; [Phase] Polyurethane A contains alkoxymethyl Cases in which O-polyurethane A contains ethyleneimino groups, and polyurethane B contains carboxyl groups.

These reactive groups react with each other by heating etc. to form a crosslinked structure, but as a polyurethane molecule, iq or 2
More than one species can participate in this cross-linked structure. In addition to polyurethane molecules, it is possible to add one or more other types of polymers that have groups that can react with the reactive groups in the polyurethane when heated, or low molecular weight substances that can react with the reactive groups in the polyurethane. It is also possible to add one or more types of groups having groups that react with each other during heating. The self-crosslinking polyurethane in the present invention can be produced by any known method. The reactive groups are polyhydroxy compounds, polyisocyanates, and chain extenders that are raw materials for polyurethane.

It can be introduced by any of the other raw materials 1, etc. Various methods are employed for producing an aqueous liquid by imparting hydrophilicity to self-crosslinking polyurethane. For example, hydrophilicity can be imparted by introducing a water-soluble salt type group such as a sulfonate, carboxylate, phosphate, or ammonium salt into the polyurethane molecule. The introduction of these water-soluble bases is a method of using substances containing these groups as raw materials for polyurethane.

Any method can be selected, such as a method in which functional groups in polyurethane molecules are modified by a salt-forming reaction such as neutralization after polyurethane production. The following substances can be used as self-crosslinking polyurethane raw materials.

(I) Polyhydroxy compound A compound having a hydroxyl group at two ends, such as aliphatic polyester, polylactone, aromatic polyester, mu polyether, polyethylene oxide, polythioether, polyacetal,
Chrycerin, trimethylolpropane.

Bisphenol A-ethylene oxide addition, dimethylolpropionic acid, sorbitol, triethanolamine, epoxy group-containing glycol, amine group-containing glycol.

Chlorine-containing glycols, carboxylate-containing glycols, and sulfonate-containing glycols.

Examples include blocked isocyanate group-containing glyfur.

(II), H-lysocyanate): 1,4-butane diisocyanate, t,S-hexane diisocyanate)
, 2,2.4- and 2,4.4-)limethylhexamethylene diisocyanate, cyclohexane diisocyanate, 4,4'-diisocyanate-diphenylmethane, 4,4'-diisocyanate-dicyclohexylmethane.

2.4- or 2,6-toluylene diisocyanate,
inphorone diisocyanate, tertiary amino group-containing polyisocyanate, epoxy group-containing polyinsyanate,
Reaction products of polyisocyanates and polyhydric alcohols, reaction products of polyisocyanates and polyamines, blocked polyisocyanates.

Examples include partially blocked polyisocyanates and polyisocyanates containing sulfonic acid groups.

(III) Chain extender: ethylene glycol, propylene glycol, butadienediol-1,3,1,4-
Hexanediol, neopentyl glycol, cyclohexanediol.

2.2'-bis(4-hydroxycyclohexyl) fluoride, diethylene glycol, dipyrene glycol, ethylenediamine.

hydrazine, piperazine, diaminodiphenylmethane,
Sulfone [[& Containing 1 recall, a blocked incyanate group-containing polyol, a carboxylic acid group-containing polyol.

Examples include epoxy group-containing polyols.

(IV) Other raw material diamino group-containing carboxylic acid salts.

Ami7-containing sulfonate, epoxy group-containing alcohol, and epoxy group-containing carboxylic acid.

Examples of M include alcohols containing ethyleneimino groups, alcohols containing acid anhydride groups, epoxy compounds containing halogens, and alcohols containing blocked isocyanate groups.

Polyurethane can be produced from these raw materials by any method, optionally subjected to post-treatments such as neutralization and protonation, and finally an aqueous polyurethane solution containing substantially no solvent can be obtained.

The thus obtained self-crosslinking polyurethane may be used alone, as a mixture of two or more of them, or as a mixture with ordinary non-crosslinking polyurethane, as a mixture with a low-molecular crosslinking agent, or with other reactive polymeric resins or reactive polymers. A mixture with other crystalline resins may be used as a binder component.

An example of a self-crosslinking polyurethane aqueous liquid is Kao Soap's UE"296A (product name Nihard Type).
and Softex IJ-100 (soft type) are representative examples.

The 111 dot type UK- and -296A contain an aromatic compound as a polyhydroxy component in the main chain structure, and the soft type Softex U-100 contains an aliphatic compound.

The mixing ratio of UE-296A and Softex [J-100 is usually 9/s to 4/6% by weight (solid content), preferably 7/3 to 515% by weight (solid content).

Next, in the present invention, silicone (Bl) is mainly composed of polyorka'nosyrogisan in which the substituents of simixane are mainly natyl groups, and in addition to the natyl groups, hydroxyl groups, α
-methylstyrene group, oxyalkylene group, unsaturated group,
Riphenyl group, trifluorophenyl group, epoxy group, vinyl group, carboxylic acid group, phenyl group, amino group,
A cyanoethyl group, an α-olefin group, a hydrogen group, a mercapto group, a norogenated alkyl group, etc. may be partially introduced as a substituent. In addition, it may have the above-mentioned organic group such as an amino group, an epoxy group, or a hydroxyl group at the terminal. Silicone (Bl preferably has a viscosity at 0' at 25°C in the range of lO senna stokes to 100,000 centistokes, and preferably has a molecular weight of s, o o o or more. The above organopolysiloxane is dissolved in an aqueous medium. It can be made aqueous by emulsification or water solubilization, or by known production methods such as an aqueous emulsion obtained by emulsion polymerization of silane or silane.

The silicone aqueous liquid thus obtained may be used alone or in a mixture of two or more. Among these, amino-modified, hydroxy-modified, and epoxy-modified dimethylpolysiloxanes are preferred from the viewpoint of stability of compatibility with the self-crosslinking polyurethane used as a coating solution.

The silicone (B) in the present invention has the effect of contributing to the running durability of a magnetic tape, particularly to the scratch resistance.

Next, in the present invention, the surface roughening substance to be mixed with the self-crosslinking polyurethane powder and the aqueous liquid (aqueous solution, dispersion, or emulsion) of silicone (Bl) is polyethylene, polytetrafluoroethylene, polyvinylidene fluoride, or polyethylene. Organic fine powder such as acrylonitrile, benzoguanamine resin, etc., or silica, alumina, titanium dioxide, kaolin, talc, graphite, etc.
Examples include fine inorganic powders such as calcium carbonate, feldspar, molybdenum disulfide, carbon black, or barium sulfate. It may be one that can be added to a polyurethane aqueous liquid or a silicone aqueous liquid.

This surface roughening material is a fine particle having an average particle size of 1111 nm or less, preferably an average particle size of 0.005 to 0.5 μm, particularly preferably 0.01 to 0.3 μm.

Furthermore, in order to avoid these water-insoluble solid fluff from settling in the aqueous dispersion, it is preferable to select ultrafine particles whose specific gravity does not exceed 3.

In the present invention, the surface roughening substance (0 has the effect of promoting the uniform formation of microprotrusions in the self-crosslinking polyurethane coating film itself and the reinforcing effect of the coating film by the fine powder itself, Coupled with the effect of contributing to scratch resistance, it imparts excellent slipperiness to the polyester film.

The main components of the present invention are self-crosslinking polyurethane, silicone (13), and a roughening substance (the mixing ratio of C1 is i+!1 (fA)+(B))/fcl=9a
/z~40/60, and prisoner/CB+=98/2~40/
60 (solid content η:v-1i!: ratio), preferably C(AI+(81,3/(C1=9515~
s O/20 (weight ratio). If the mixing ratio of silicone (13) is too low, running durability (especially scratch resistance) will decrease, and if it is too high, the adhesion between the coating material and the base material will be reduced, and the coating film will become sticky. The slipperiness of the film decreases. Also, roughened substances*
(If the mixing ratio of C1 is too small, the added m L
The slipperiness of the film decreases due to a decrease in the uniform protrusion formation effect of the T+i substance as fine protrusion forming substances tq in the coating film, and a decrease in the reinforcing effect of the fine powder itself on the coating film. In addition, if this ratio is too high, the ratio of surface roughening substances will increase, reducing the adhesion between the substrate and the substrate, and making the coating film brittle. The durability of the slip-facilitating effect is impaired because the coating layer is destroyed and the coating layer is worn away by the frictional force of such a degree.

The self-crosslinking polyurethane powder and the silicone (Bl) and the surface roughening substance (C1) may be mixed in the form of an aqueous dispersion. If necessary, an emulsifier may be added to the planarized substance and the mixture may be stirred and dispersed.

In the present invention, in order to enable a coating film to be smoothly applied to the surface of a polyester film before the oriented crystallization process is completed, the film surface is subjected to corona discharge treatment as a preliminary treatment, or the coating composition is In addition, it is preferable to use a chemically inert surfactant together with this.

Such surfactants lower the surface tension of the aqueous composition by 40 d.
It promotes sagging to a polyester film that can be lowered to 7 cm or less, such as polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, and sorbitan fatty acid ester.

Glycerin fatty acid ester, fatty acid metal soap.

Alkyl sulfate, alkyl sulfonate, alkyl sulfosucci aL4. Examples include quaternary ammonium chloride, alkylamine hydrochloride, silicone-based, silicone-fluorine-based, and fluorine-based surfactants, and amphoteric surfactants.

The coating composition of the present invention contains a crosslinking agent and a crosslinking accelerator, as long as the contributing effects thereof are not lost.

There is no problem in crystallizing with a wide range of additives such as antistatic agents, lubricants, ultraviolet absorbers, resins, etc., and using them together. In addition, in order to achieve quick drying and improve solubility, alcohol, ester, or ether-based IfJ media may be added to the aqueous composition within a range that does not significantly interfere with the environment during the film forming process.
You can also add additional information.

According to the IC of the present invention, the aqueous solution, aqueous dispersion or emulsion thus prepared is applied to the surface of the unstretched or at least uniaxially stretched polyester film before the crystal orientation is completed. In this case, the solid content concentration of the aqueous solution, aqueous dispersion, or emulsion is usually 50 wt% or less, preferably 2 Owt% or less, and the viscosity is 200 Cps.
Below, preferably 50 cps or less is appropriate.

These aqueous solutions, aqueous dispersions or emulsions are used in an amount of about 0.5 to about 20 g, preferably about 2 g, per running film xi.
An amount of ~10.9 is applied in a rigid manner. In other words, in the biaxially stretched film finally obtained,
About 0.001 to about IIi per 1 d on one surface of the film,
Preferably about 0.01 to 0.5 g, more preferably about 0
．． It is applied to the film in an amount to form a solids content of 0.03 to about o.a.y.

According to the invention, the above-mentioned aqueous liquid, ie, an aqueous solution, aqueous dispersion or emulsion, is applied to a running unstretched or uniaxially stretched film. Even if this aqueous solution or aqueous dispersion is applied to a film after completing crystal orientation by biaxial stretching heat setting and then heated, an easily slippery film having a large number of fine protrusions on the film surface can be manufactured. I can't.

According to the present invention, the aqueous liquid is preferably applied to the film immediately after being uniaxially stretched, and then led to a tenter for biaxial stretching and heat setting. As the polyester film is stretched, the area of the coated material expands, and the water is volatilized by heating, which converts the biaxially stretched film into a solid coating layer with many microscopic protrusions through a crosslinking reaction. and is firmly coated on the biaxially stretched film surface.

In a non-crosslinking polyurethane aqueous solution or aqueous dispersion, even after the base layer drawing process and heat treatment process, the water is simply volatilized and a flat coating layer is formed, and the effect of developing lubricity is not achieved. low.

An example of such an aqueous dispersion of non-crosslinked bone polyurethane is /1 Idlan HW-140 manufactured by Nippon Reichhold.
, Bondic 1150. 115ONS, Bayer's Impranil DLH and DLN, or Sumitomo Bayer's Desmocol KA-8100. Same 80 (+6 (
All of them are 躺品名).

The reason for the appearance of microprotrusions in 1 m of coating in the present invention is not fully understood, but the unique effects of self-crosslinking polyurethane coatings and polyester films are based on drying changes caused by the self-crosslinking reaction of the coating film that progresses when heated. It is presumed that this is caused by a synergistic effect with the stretching effect of the coating film due to the area expansion accompanying the stretching.

In the present invention, the aqueous liquid described above can be applied to one or both sides of an unoriented or -axially stretched film. The slippery biaxially stretched film of the present invention obtained by coating only on one side is
It has a dual surface structure in which one surface has a large number of microprotrusions and the other surface is smooth, and can be particularly suitably used as a material for magnetic tape.

The aqueous liquid can be applied by technical means known per se, such as reverse coating (bottom feed 3 reverse, bottom feed 4 reverse, 2 a-le reverse or top feed 3 reverse, etc.), Kissmeyer coating, gravure coating (direct Gravure or offset gravure), slot die coating, curtain coating, etc. can be used.

According to the present invention, the slippery film of the present invention having the above-mentioned dual surface structure preferably contains the above-mentioned aqueous liquid,
It can be advantageously produced by a method in which coating is applied from the bottom surface of a uniaxially stretched film that runs substantially horizontally away from the nip roller group using an a-le coater.

The aqueous solution, aqueous dispersion, or emulsion applied to the polyester surface to a uniform thickness by the above-mentioned method is applied to the surface 81 of the unsolidified coating film as the film is stretched.
is expanded and heated to drive off the water and transform into a thin solid coating layer with a large number of microprojections on the biaxially stretched film surface, which is firmly adhered to the biaxially stretched film surface.

According to the present invention, the aqueous liquid is converted into a solid coating film having a large number of minute protrusions, as described above, by a step of stretching the substrate and a heat treatment step.

Note that heating is required to form the large number of microprotrusions described above, and for example, when an aqueous liquid is applied to an axially stretched film and then air-dried without heating, the coating layer of the film is substantially Therefore, it is impossible to form a large number of microprotrusions that retain their shape.

This heating is preferably carried out at a temperature of about 100 to about 240°C for about 1 to about 20 seconds.

Furthermore, the formation of a solid coating layer with a large number of microprojections
For example, it is subtly influenced by the stretching ratio, the composition of the aqueous liquid applied to the film, the coating 1, etc.

Effects of the Invention The easily slippery biaxially stretched polyester film of the present invention has extremely excellent slip properties, as will be explained later using specific data in Examples, and excellent slip properties are required. 4 in various fields? It is suitably used as a material for magnetic tape.

Various values herein are measured and defined as follows.

(11 CLA value Using a stylus type surface roughness meter (Surcom3B) manufactured by Tokyo Seimitsu Co., Ltd., under the conditions of a needle radius of 2 μm and a load of 0.1994: When a part of measurement length L (standard length 2 mm) is extracted and the roughness curve is expressed as Y=ftx) with the center line of this extracted part as the X axis and the Y axis in the direction of vertical magnification, the following The value given by the formula is expressed in μm.

In this measurement, 8 pieces were measured with a standard length of 0.25 mm, 3 pieces from the direction with the largest value were excluded, and the average value of the 5 pieces was expressed.

(2) Coefficient of Dynamic Friction (Running Properties) The attached diagram shows the coefficient of kinetic friction μ for evaluating film running properties.
FIG. 1 is a schematic diagram for measuring k (device 1 used: Japan Automatic Control, NJS 101 type). In the drawing, 1 is a feeding reel, 2 is a tension controller, 3, 4,
6゜B+9+11 is free roll, 5 is tension detector (inlet), 7 is chrome plated fixing pin (s1m9!5
), 10 is a tension detector (exit), 12 is a guide a
-A and 13 indicate take-up reels, respectively.

As shown in the figure, in an atmosphere of 20℃so%RH, the treated surface force was applied to a fixing pin with an outer diameter of 5m (xsz/, x
The film is passed through the film in contact with so) k radians and is subjected to moving friction at a speed of 3.3 degrees per second. And when the tension controller 2 is adjusted so that the inlet tension force is 3 Q gk, the outlet tension is 'l'! Calculate the dynamic friction coefficient μk using the formula (10).

Note that μ is displayed as the value after 100 baths.

<31 Fill resistance After 100 baths, it was observed whether there was any material force deposited on the fixing pin. A case where almost no deposit force is observed is indicated by ○, a case where there is some evidence of adhesion is indicated by △, a large number of X, and a case of S is indicated by X.

(4) Scratch Resistance After the film was scratched 100 times with a fixing pin, the abrasion state (degree of scratch occurrence) on the film surface was observed. scratch l
I: ○ indicates that it is hardly observed, and x indicates that it occurs to some extent.

(5) Film Friction Coefficient The friction coefficient between the coated surface and the polyethylene terephthalate film (untreated) was measured using a slippery measuring device manufactured by Toyo Tester Co., Ltd.

Example The present invention will be further explained below with reference to Examples.

Comparative Example 1 Polyethylene terephthalate (crystalline heat of fusion 9.5 ctt/l) containing no inorganic filler and having an intrinsic viscosity of 0.62 as determined in orthochlorophenol at 25°C
was extruded from the nozzle using an extruder, and then placed on a drum cooled to 40°C while applying electrostatic charge to a thickness of 152 μm.
This was then stretched by tc-3.6 times in the longitudinal direction on a metal roll heated to 93°C.

Next, the IC was introduced into the tenter, passed through a preheating zone at 98°C, and then 3. Stretched 9 times, further heat-set at 225℃ for 6.3 seconds to complete crystal orientation, and then rolled up the tensicon 9 while slitting the edges.
．． Scouring was carried out at 500so+width under the conditions of 8+9. The final film had an average thickness of 12.1 μm.

Wrinkles occurred in the film roll due to poor mutual sliding between the films. Once these wrinkles occur, they propagate and concentrate on the surface layer one after another, resulting in a rolled-up appearance that does not conform to the shape of the bottom product, with one side of the a-ru edge being hard and the center being soft. .

Separately, the winding tension was set to the maximum and the winding was carried out with a weight of 4.66 kg, but in addition to the edges being uneven, wrinkles were also observed, and a perfect result could not be obtained. Attempts were made to microslit this film into 172 inches, but this was not possible.

The results obtained are shown in Table 1.

Example 1 30wt4 self-emulsion of self-crosslinking polyurethane (manufactured by Hanadama Soap; trade name: UE-29t+A, hard type)
45! (' is part (solid content), 10wt% self-emulsified liquid of self-crosslinking polyurethane [manufactured by Ishi Tamasap a′υ;
Product name Nftecsu U-100, Soft type 330
Parts by weight (as solids) of amino-modified silicone
wt96 emulsion liquid 10 parts by weight (as solid content), 19 wt4 aqueous dispersion of colloidal silica (average particle size 40-50 mμ) 10 parts by weight (as solid content) Yohipolyoxyethylene nonylphenyl ether (HLB
= 12.8; NOF MlltL Product name NS20
8.5) 5 parts by weight were thoroughly mixed first with a homogenizer and then with an ultrasonic disperser to prepare a coating composition. This coating composition was diluted and dissolved in ion-exchanged water, and the total solid content was 91. It was made into a coating liquid.

Next, in the same method for producing a biaxially stretched film as in Comparative Example 1, [at a position immediately before the uniaxially stretched film, which has been vertically stretched, enters the tenter, the above coating liquid was applied to one side of the film using three rolls. Apply it evenly from the coater head.

The amount of coating liquid applied is the above - Axial Stretched Film II? The weight was about 4 g per 1' (this weight corresponds to about 0.092 SI K per 1 m' in the biaxially stretched film described below).

The uniaxially stretched film coated on one side was introduced into a tenter and passed through a 98°C preheating zone, stretched 3.9 times in the transverse direction at 105°C, and then heat-set at 225°C for 6.3 seconds (coating liquid The total time the coated film was heated corresponds to 11 seconds).

As a result, the biaxially stretched film could be rolled up with a tension of 9.8 kg without wrinkles. This film was microslit into half-inch width, and
Fifty-two m4Q tapes were manufactured. During this time, the film was successfully slit without any trouble.

Table 1 shows the surface properties, runnability, etc. of the film of the present invention.

As is clear from comparison with the film obtained in Comparative Example 1 (to which no coating liquid was applied), the film of the present invention has extremely excellent basic properties as a base film for special Kf&K tape.

When the treated surface was deposited with aluminum and observed under 400x magnification using a differential interference microscope, it was confirmed that a large number of microscopic protrusions were formed.Comparative Example 2 Comparative Example 1771! The same coating composition as in Example 1 was applied to one side of the biaxially stretched film obtained under the film conditions using a Mayer bar, and the coating composition was applied to about 11/rr? (wet) and approximately 4I//m'(
Apply two kinds of di-A coating so that it becomes wet), and
After pre-drying at 0° C. for 1 minute, the film was then tightened around the circumference with a wooden frame and subjected to a thermal exotherm for 10 seconds in an atmosphere at a temperature of about 225° C. After this, aluminum was vapor-deposited on the coated side, and the surface layer was observed using a differential interference microscope at a magnification of 400 times. However, almost no microprojections were formed, and a flat film surface was present. It wasn't too tilted.

On the other hand, the coefficient of static friction and the coefficient of dynamic friction of the slippery on the treated and untreated surfaces were both 0.5 to 0.7, and although the effect of the coating was recognized, it was not at a level that was outstandingly good.

Comparative Example 3 40 wL% self-emulsifying liquid of non-crosslinking polyurethane [manufactured by Bayer AG, trade name: Impranil DLH] 75! 20 wt% emulsion liquid of amine-modified silicone, 10 M 1 it part (as solid content), colloidal silica moisture content [average particle size 40-50 tnB]
) 10 Jushuto (as a rail type component) and polyoxyhenalene nonyl phenyl ether [manufactured by NOF@,
Trade name NS20 a, s) Parts by weight were adjusted in the same manner as in Example 1 to obtain a coating liquid with a total solid content concentration of 9%.

A biaxially stretched film was produced in exactly the same manner as in Example 1, including the coating amount for the −axially stretched film.

The same phenomenon as in Comparative Example 1 was observed, with poor mutual sliding between the films and wrinkles. Furthermore, 31:30' of silica
When we tried increasing the Mt part (as a solid content), although the winding property was somewhat improved, it was not possible to avoid the occurrence of wrinkles, and the runnability test of 1/2 inch width Tates was also slippery. was bad.

Example 2 26 parts by weight of a 30 wt% self-emulsified liquid of self-crosslinking polyurethane (Hanadama Soap 11'L trade name UE-296A) (
(as solids), 1o wt of self-crosslinking polyurethane
% self-emulsifying liquid [manufactured by Hanadama Soap, product name: Softex (
J Zoo) 17'ii parts (as solid content), 30wt% emulsion liquid of epoxy modified silicone, 9mt
-fj 1 part (as solid content), colloidal silica aqueous dispersion (average particle size 12-15 fiμ) 43 parts (as solid content) Yohi polyoxyethylene nonylphenyl ether [manufactured by NOF ■, product name N52os, s )s parts by weight were adjusted in the same manner as in Example 1 to obtain a coating liquid with a total solids concentration of 5.

In addition, coating salmon with -axially stretched film is approximately 2.5/l/d.
[Wet; about 0.032 for biaxially stretched film! iI
A biaxially stretched film was produced in exactly the same manner as in Example 1, except that the film was coated at a dry coating temperature of 1/m' (equivalent to dry).

As in Example 1, it could be rolled up well and no trouble occurred during slitting.

Table 1 shows the surface characteristics, runnability, etc. of the film of this example.

Example 3 30 wL% self-emulsifying liquid of self-crosslinking polyurethane (manufactured by Hanadama Soap ■, trade name UE-296A) 42 parts by weight (as solid content), 10 wt% self-emulsifying liquid of self-crosslinking polyurethane [Hanadama Soap Made by ■, product name Soft Tux [J-
100) 28 parts by weight (as solid content), 10 parts by weight of 40 wt% emulsion liquid of hydroxy-modified silicone (
(as solid content), 25wt of inoctyl myristate
% emulsion liquid 5 parts by weight (as solid content).

Colloidal silica aqueous dispersion (average particle size 40-50 mμ)
10 parts by weight (solid content) and 5 parts by weight of polyoxyethylene nonyl phenyl ether (IE211 manufactured by Seishi Co., Ltd., trade name N5208.5) were prepared in the same manner as in Example 1, and the total solid content was 2%. A coating solution of 9 cm was used.

In addition, including the coating amount of Ali in the -axis stretched film, Example 1
When a biaxially stretched film was produced in exactly the same manner as above, it could be rolled up well and no troubles occurred during slitting.

Table 1 shows the surface characteristics, runnability, etc. of the film of this example.

Example 4 A o wt% self-emulsion of self-crosslinking polyurethane [
Made by Hanadama Soap ■, product name UE-296A) 45 parts by weight (
(as solid content), 10 wt% of self-crosslinking polyurethane
Self-emulsifying liquid [manufactured by Hanadama Soap■, white product name Softec Sue]
J-100) 30 parts by weight (as solid content) 9 3 owt% emulsion liquid of epoxy-modified silicone 10 parts by weight (as solid content), polyethylene tetrafluoride [Taikin Kogyo (1'll!l!!, trade name: LeBron) 10 parts by weight of nonionic surfactant NS 208.5 (manufactured by NOF 4 Co., Ltd., trade name), parts by weight of Si, prepared in the same manner as in Example 1, and total solid Minute concentration ls%
It was made into a coating liquid.

Next, at a position immediately before the single-motion stretched film of Comparative Example 1, which had been vertically stretched, reached the tenter, the above coating liquid was uniformly applied onto one side of the film using a coke head consisting of three rolls.

The coating amount was approximately 71/m' for a uniaxially stretched film (wet; equivalent to approximately 0, zs 7 l/i dry for a biaxially stretched film).The uniaxially stretched film that had been coated on one side was placed in a tenter. , passed through a preheating zone at 98°C, stretched 3.9 times in the same direction at 105°C, and further stretched 2 times.
Heat set at 35°C for 10 seconds (the total time the film coated with the coating solution was heated corresponds to 20 seconds)
However, the film could be rolled up well and no trouble occurred during slitting. Table 1 shows the surface characteristics, runnability, etc. of this example.

Example 5 The magnetic paint shown below was applied to the non-treated side of the smooth biaxially oriented polyester film obtained in Example 1 using gravure cooling, and the magnetic paint layer was smoothed using a doctor knife. While the paint was still dry, it was oriented using a conventional method, and then introduced into an oven for dry curing. Further, the coating surface was made uniform by calendering, and a tape with a width of 172 inches was prepared with a magnetic layer of about 4 .mu.m thick. In addition, there is no trouble on the sides during each processing and process of the upper surface, and the running durability (scratching resistance,
Scratch resistance) was also good.

Composition of magnetic paint Acicular Fe particles 100JJ (bone part (average major axis 0.4μ; specific surface area approximately 40rrl19)
ESLETSUQ A'lQ 〃 (Sekisui Chemical Co., Ltd.; vinyl chloride/vinyl acetate copolymer) Nirabolan 2304 10// (Nippon Polyurethane Co., Ltd.; polyurethane elastomer) Coronate L 5 n (Nippon Polyurethane Co., Ltd.: polyincyanate) Lecithin 2 〃 Additive (Lubricant, silicone resin) 1 M E K
75 // M I B K 75 tt Toluene 75 〃

[Brief explanation of the drawing]

The figure shows the coefficient of kinetic friction (μk) used to evaluate film runnability.
) is a schematic diagram for measuring. i: s out t, reel, 2: tension controller,
3, 4, 6, 8, 9.11: Freeroll. 5: Tension detector (inlet), 7: Fixed pin, 10:
Tension detector (outlet).

Claims (1)

[Claims] Before crystal orientation is completed, an aqueous solution, aqueous dispersion, or emulsion composition containing a self-crosslinking polyurethane powder, silicone (Bl), and a roughening substance (Q) with an average particle size of 1 μm or less as the main components is applied to the surface of the polyester film before crystal orientation is completed. An easily slippery polyester film obtained by applying the composition and subjecting the composition to a crosslinking reaction on the film surface to form a coating film having a large number of microprojections.